The present invention relates to a thermal transfer recording material, a thermal transfer recording method, an ink, a toner, and a color filter utilizing specified dyes.
Heretofore, there have been investigated many color image recording methods in order to prepare color hard copies. Examples of these are ink jet, electrophotography, thermal transfer, and silver halide photographic materials. Of these, thermal transfer recording exhibits advantages such as ease of operation and maintenance, and having the possibility to decrease the dimensions of the apparatus and running cost for printing.
In said thermal transfer recording, coloring materials employed in thermal transfer recording materials (hereinafter occasionally referred to as thermal transfer materials) are critical components. With the purpose of improving the stability of formed images, especially to improve fixability and light fastness of images, thermal transfer materials and image forming methods were disclosed. Examples of these are, Japanese Patent Publication Open to Public Inspection Nos. 59-78893, 59-109349, and 60-2398. Images formed employing thermally transferred dyes capable of being chelated (which are called post-chelate dyes or metal chelate dyes in the present specification), disclosed in said patent publications, exhibit excellent light fastness and excellent fixability. However, the sensitivity of thermal transfer materials and storage stability of the materials themselves does not meet full satisfaction. In addition, when full-color images are prepared using post-chelate dyes, it has been necessary to improve the color reproduction due to the following reason. When the chelate reaction does not fully proceed, the absorption of unreacted post-chelate dyes becomes observable due to the great color difference between the post-chelate dyes and unreacted dyes, and in addition, the post-chelate dyes sometimes exhibits undesirable absorption to obtain a desirable full-color image.
Specifically, Japanese Patent Publication Open to Public Inspection Nos. 3-143684, 3-143686, and 9-257947, and Japanese Patent Application No. 11-60123 describe thermal transfer recording materials employing dyes comprising a pyrazolopyrimidine-7-one parent nucleus. These dyes to some extent overcome the problems as mentioned above, but their improvement has been insufficient. Specifically, storage stability at high temperature and high humidity (heat and moisture resistance) and storage stability under light illumination (light fastness) has been insufficient, and consequently further improvement has been demanded.
Further, said metal chelate dyes, when employed in an ink for ink jet printing, are required to result in compatibility with several recording systems (such as 1: a system which press-ejects liquid droplets utilizing electromechanical conversion of a piezo element, 2: a system which press-ejects droplets while generating air bubbles utilizing electrothermal conversion, and 3: a system which suck-ejects liquid droplets utilizing electrostatic force), high recording density and excellent image color, excellent image stability such as light fastness, heat resistance and water resistance, rapid fixing onto the media to be recorded and no bleeding after recording, excellent stability as ink, no problem regarding safety, and low cost. From such viewpoints, various types of ink jet recording liquid have been proposed and investigated. However, the types of recording liquid, which satisfy most of demands at the same time, are extremely limited. In color image recording, employing yellow, magenta, cyan, and black, a variety of dyes and pigments, having C.I. number, which are indicated in Color Index and conventionally known in the art, have been investigated. However, there are still needed further efforts to improve the properties of dyes such as durability, light fastness, and spectral absorption characteristics in terms of color reproduction which results in high color vividness.
Further, when said dyes are employed in color toners, in color copiers and color laser printers employing an electrophotographic system, toner, which is prepared by dispersing colorants into resinous particles or by adhering colorants onto the surface of resinous particles, is generally employed. When the method in which colorants are adhered onto the surface of resinous particles is employed, it is difficult to achieve sufficient coloring effects due to coloration of only the surface. Further, problems occur in which due to releasing of colorants from the surface, charging properties vary and the surface of fixing rollers is stained. Due to that, toner, which is prepared by dispersing said colorants into the interior of particles, is increasingly being employed. Listed as performance required for said toner are color reproduction and image transparency and light fastness when employed for overhead projectors (hereinafter referred to as OHP). Japanese Patent Publication Open to Public Inspection Nos. 62-157051, 62-255956 and 6-118715 disclose toners which are prepared by dispersing pigments as colorants into particles. The resultant toners exhibit good light fastness, but tend to coagulate due to the fact that the pigments are insoluble. As a result, problems such as a decrease in transparency and color variation have occurred. On the other hand, Japanese Patent Publication Open to Public Inspection Nos. 3-276161, 2-207274, and 2-207273 disclose toners in which dyes are employed as colorants. The resultant toners result in high transparency and no color variation, but results in problems with light fastness.
Still further, high transparency is required for color filters, whereby a method called the dying method has been practiced in which coloration is performed employing dyes. For example, it is possible to produce color filters employing the following steps. Photosensitive materials, which are subjected to dying, are applied onto a substrate such as glass, and subsequently, pattern exposure of one of said filter colors is carried out. The unexposed part is washed off in the development process, and the remaining pattern part is dyed employing the dye for said filter color. This operation is successively repeated for all other filter colors. This method results in color filters with excellent optical properties due to high transparency obtained by using dyes. However, light fastness and heat resistance has been limited. As a result, instead of dyes, organic pigments, which exhibit excellent light fastness and heat resistance, have been employed. However, it has been difficult to produce pigment-employed filters which exhibit the optical properties obtained by dye-employed filters.
It is desirable that said dyes, which can be used for each use, are provided with the following properties in common. Namely, listed as requirements are preferable color for color reproduction, optimal spectral absorption properties, high image durability such as light fastness, heat resistance, water resistance, and chemical resistance, and a high molar absorption coefficient.
An object of the present invention is to provide a thermal transfer recording material to prepare images which exhibit high sensitivity, excellent color reproduction, and excellent image retaining quality, and a thermal transfer recording method using said recording material. Another object of the present invention is to provide an ink jet recording ink which exhibits optimal spectral absorption characteristics, and high image durability which are suitable for use. Another object of the present invention is to provide a color toner and a color filter having optimal spectral absorption characteristics, and high image durability.
The inventors of the present invention performed diligent investigations to overcome said problems. As a result, it was discovered that the objects of the present invention were achieved by employing novel dyes having a pyrazolopyrimidine-7-one parent nucleus.
Namely, aforesaid objects of the present invention are achieved employing the embodiments described below.
1. A thermal transfer recording material comprising a support having thereon an image transferring layer containing a coloring material represented by Formula (I), 
wherein each R11 and R12 is independently a substituted or unsubstituted aliphatic group; R13 is a substituent and n is an integer of 0 to 4, provided that when n is 2 or more, a plurality of R13s are the same or different; R14 is an alkyl group; and each R15 and R16 is independently an alkyl group having 3 to 8 carbon atoms.
2. The thermal transfer recording material of item 1, wherein R14 is a secondary alkyl group.
3. The thermal transfer recording material of item 1, wherein the coloring material is represented by Formula (II), 
wherein each R21 and R22 is independently a substituted or unsubstituted aliphatic group; R23 is a substituent and n is an integer of 0 to 4, provided that when n is 2 or more, a plurality of R23s are the same or different; R24 and R25 each are an alkyl group; R26 is a branched chain alkyl group; and R27 is an alkyl group other than methyl group.
4. The thermal transfer recording material of item 3, wherein R26 is a branched chain alkyl group having 3 to 8 carbon atoms.
5. The thermal transfer recording material of item 3, wherein the coloring material represented by Formula (II) has a molecular weigh of 400 to 500.
6. A thermal transfer recording method, comprising the steps of:
(a) superimposing an image receiving material onto a thermal transfer recording material comprising a support having thereon an image transferring layer containing a coloring material represented by Formula (I) or Formula (II),
(b) applying heat onto the thermal transfer recording material to form an image; and
(c) separating the thermal transfer recording material and the image receiving material from each other, 
wherein each R11 and R12 is independently a substituted or unsubstituted aliphatic group; R13 is a substituent and n is an integer of 0 to 4, provided that when n is 2 or more, a plural R13s are the same or different; R14 is an alkyl group; and each R15 and R16 is independently an alkyl group having 3 to 8 carbon atoms, 
wherein each R21 and R22 is independently a substituted or unsubstituted aliphatic group; R23 is a substituent and n is an integer of 0 to 4, provided that when n is 2 or more, a plurality of R23s are the same or different; R24 and R25 each are an alkyl group; R26 is a branched chain alkyl group; and R27 is an alkyl group other than methyl group.
7. The thermal transfer recording method of item 6, wherein the image receiving material comprises a support having thereon a layer containing a compound comprising a metal ion capable of forming a metal complex dye with the coloring material in the thermal transfer recording material during the step (b).
8. An ink for ink jet printing, which comprises a metal complex dye prepared from a compound containing a metal ion and a coloring material represented by Formula (I) or Formula 
wherein each R11 and R12 is independently a substituted or unsubstituted aliphatic group; R13 is a substituent and n is an integer of 0 to 4, provided that when n is 2 or more, a plurality of R13s are the same or different; R14 is an alkyl group; and each R15 and R16 is independently an alkyl group having 3 to 8 carbon atoms, 
wherein each R21 and R22 is independently a substituted or unsubstituted aliphatic group; R23 is a substituent and n is an integer of 0 to 4, provided that when n is 2 or more, a plurality of R23s are the same or different; R24 and R25 each are an alkyl group; R26 is a branched chain alkyl group; and R27 is an alkyl group other than methyl group. Another objects of the present invention are achieved employing the embodiments described below.
I. A toner for an electrophotographic recording, which comprises a metal complex dye prepared from a compound containing a metal ion and a coloring material represented by Formula (I) or Formula (II).
II. A color filter comprising a metal complex dye prepared from a coloring material represented by Formula (I) or Formula (II) and a compound containing a metal ion.